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Atom probe tomography was used to study the redistribution of platinum and arsenic atoms after Ni(Pt) silicidation of As-doped polycrystalline Si. These measurements were performed on a field-effect transistor and compared with those obtained in unpatterned region submitted to the same process. These results suggest that Pt and As redistribution during silicide formation is only marginally influenced by the confinement in microelectronic devices. On the contrary, there is a clear difference with the redistribution reported in the literature for the blanket wafers. Selective etching used to remove the non-reacted Ni(Pt) film after the first rapid heat treatment may induce this difference. [ABSTRACT FROM AUTHOR]

Abstract: Reliability and yield of nano-electronic devices can be seriously affected by the presence of surface contamination, even at low concentration. The microelectronics industry is, thus, in need for a quantitative, highly sensitive surface analysis technique capable of detecting both elementary and molecular species present at the surface. Time-of-Flight Secondary Ion Mass Spectrometry (ToF-SIMS) provides a submicronic lateral resolution and excellent sensitivity with high secondary ion yields on a broad mass range but, nevertheless, remains a qualitative technique. To convert normalized ion intensities into concentrations and, thus, to provide reliable quantification, the so-called relative sensitivity factors (RSFs) need to be determined. In earlier studies, ToF-SIMS RSFs for trace metals were determined from the calibration of ToF-SIMS positive ion intensities against quantitative analysis techniques able to determine a surface coverage such as vapour phase decomposition inductively coupled plasma mass spectrometry (VPD-ICP-MS) or total reflection X-ray fluorescence (TXRF) results. Here, the aim is to quantify elementary anionic minority species (S, Cl, P, Br). Deliberately contaminated samples were prepared and analyzed with ToF-SIMS and several quantitative surface analytical techniques like TXRF, liquid phase extraction ionic chromatography (LPE-IC) or VPD-ICP-MS. None of these latter techniques can by itself successfully handle all the anionic species cases and ToF-SIMS turns out to be the more versatile and precise characterization technique in this context. [Copyright &y& Elsevier]

Abstract: Recent time-of-flight secondary ion mass spectrometry studies using primary ion cluster sources such as Au n +, SF5 +, Bi n + or C60 + have shown the great advantages in terms of secondary ion yield enhancement and ion formation efficiency of polyatomic ion sources as compared to monoatomic ion sources like the commonly used Ga+. In this work, the effective gains provided by such a source in the static ToF-SIMS analysis of microelectronics devices were investigated. Firstly, the influence of the number of atoms in the primary cluster ion on secondary ion formation was studied for physically adsorbed di-isononyl phthalate (DNP) (plasticizer) and perfluoropolyether (PFPE). A drastic increase in secondary ion formation efficiency and a much lower detection limit were observed when using a polyatomic primary ion. Moreover, the yield of the higher mass species was much enhanced indicating a lower degree of fragmentation that can be explained by the fact that the primary ion energy is spread out more widely, or that there is a lower energy per incoming ion. Secondly, the influence of the number of Bi atoms in the Bi n primary ion on the information depth was studied using reference thermally grown silicon oxide samples. The information depth provided by a Bi n cluster was shown to be lowered when the number of atoms in the aggregate was increased. [Copyright &y& Elsevier]

The Fully-Depleted Silicon-on-Insulator (FD-SOI) technology for advanced CMOS devices is based on SOI substrates formed by an ultra-thin Si or SiGe film on a thick insulator. A reduction of parasitic resistances of such CMOS components is obtained with the Raised Source and Drain (RSD) technology. In this work we show that modifying the Siconi™ plasma-based etching process widely used in microelectronic and/or combining it to wet-etching methods allows to improve the principal steps of fabrication of RSD FD-SOI CMOS devices. More precisely, using sampling areas on 300 mm wafers that simulate the principal stages of FD-SOI building, (i) we show that a modified SiCoNi process may be used to increase the etching selectivity necessary to dissolve the oxide layer while maintaining a low-k spacer of high quality, (ii) we propose a combination of optimized SiCoNi-dry and wet etching that reduces the post-etching roughness and the contamination level of the channel surface before the subsequent epitaxy. [ABSTRACT FROM AUTHOR]

Abstract: Different FIB-based sample preparation methods for atom probe analysis of transistors have been proposed and discussed. A special procedure, involving device deprocessing, has been used to analyze by APT a sub-30nm transistor extracted from a SRAM device. The analysis provides three dimensional compositions of Ni-silicide contact, metal gate and high-k oxide of the transistor gate. [Copyright &y& Elsevier]